[x86_64] PR target/106481: Handle CONST_WIDE_INT in REG_EQUAL during STV.
Commit Message
This patch resolves PR target/106481, and is an oversight in my recent
battles with REG_EQUAL notes during TImode STV (see PR target/106278
https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598416.html).
The patch above's/current behaviour is that we check that the mode of
the REG_EQUAL note is TImode before using PUT_MODE to set it to V1TImode.
However, the new test case reveals that this doesn't consider REG_EQUAL
notes that are CONST_INT or CONST_WIDE_INT, i.e. that are VOIDmode,
and so STV produces:
(insn 85 84 86 2 (set (reg:V1TI 113)
(reg:V1TI 84)) "pr106481.c":13:3 1766 {movv1ti_internal}
(expr_list:REG_EQUAL (const_wide_int 0x0ffffffff00000004)
(nil)))
which causes problems as the const_wide_int isn't a valid immediate
constant for V1TImode. With this patch, we now generate the correct:
(insn 85 84 86 2 (set (reg:V1TI 113)
(reg:V1TI 84)) "pr106481.c":13:3 1766 {movv1ti_internal}
(expr_list:REG_EQUAL (const_vector:V1TI [
(const_wide_int 0x0ffffffff00000004)
])
(nil)))
This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, both with and without --target_board=unix{-m32},
with no new failures. Ok for mainline?
2022-08-01 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
PR target/106481
* config/i386/i386-features.cc (timode_scalar_chain::convert_insn):
Convert a CONST_SCALAR_INT_P in a REG_EQUAL note into a V1TImode
CONST_VECTOR.
gcc/testsuite/ChangeLog
PR target/106481
* gcc.target/i386/pr106481.c: New test case.
Thanks again,
Roger
--
Comments
On Mon, Aug 1, 2022 at 3:43 PM Roger Sayle <roger@nextmovesoftware.com> wrote:
>
>
> This patch resolves PR target/106481, and is an oversight in my recent
> battles with REG_EQUAL notes during TImode STV (see PR target/106278
> https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598416.html).
>
> The patch above's/current behaviour is that we check that the mode of
> the REG_EQUAL note is TImode before using PUT_MODE to set it to V1TImode.
> However, the new test case reveals that this doesn't consider REG_EQUAL
> notes that are CONST_INT or CONST_WIDE_INT, i.e. that are VOIDmode,
> and so STV produces:
>
> (insn 85 84 86 2 (set (reg:V1TI 113)
> (reg:V1TI 84)) "pr106481.c":13:3 1766 {movv1ti_internal}
> (expr_list:REG_EQUAL (const_wide_int 0x0ffffffff00000004)
> (nil)))
>
> which causes problems as the const_wide_int isn't a valid immediate
> constant for V1TImode. With this patch, we now generate the correct:
>
> (insn 85 84 86 2 (set (reg:V1TI 113)
> (reg:V1TI 84)) "pr106481.c":13:3 1766 {movv1ti_internal}
> (expr_list:REG_EQUAL (const_vector:V1TI [
> (const_wide_int 0x0ffffffff00000004)
> ])
> (nil)))
>
>
> This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
> and make -k check, both with and without --target_board=unix{-m32},
> with no new failures. Ok for mainline?
>
>
> 2022-08-01 Roger Sayle <roger@nextmovesoftware.com>
>
> gcc/ChangeLog
> PR target/106481
> * config/i386/i386-features.cc (timode_scalar_chain::convert_insn):
> Convert a CONST_SCALAR_INT_P in a REG_EQUAL note into a V1TImode
> CONST_VECTOR.
>
> gcc/testsuite/ChangeLog
> PR target/106481
> * gcc.target/i386/pr106481.c: New test case.
OK, but how about we restructure the conditions a bit, like in the
attached patch?
Uros.
diff --git a/gcc/config/i386/i386-features.cc b/gcc/config/i386/i386-features.cc
index e4cc4a30590..e3ecc22580a 100644
--- a/gcc/config/i386/i386-features.cc
+++ b/gcc/config/i386/i386-features.cc
@@ -1353,8 +1353,15 @@ timode_scalar_chain::convert_insn (rtx_insn *insn)
if (GET_MODE (dst) == V1TImode)
{
tmp = find_reg_equal_equiv_note (insn);
- if (tmp && GET_MODE (XEXP (tmp, 0)) == TImode)
- PUT_MODE (XEXP (tmp, 0), V1TImode);
+ if (tmp)
+ {
+ if (GET_MODE (XEXP (tmp, 0)) == TImode)
+ PUT_MODE (XEXP (tmp, 0), V1TImode);
+ else if (CONST_SCALAR_INT_P (XEXP (tmp, 0)))
+ XEXP (tmp, 0)
+ = gen_rtx_CONST_VECTOR (V1TImode,
+ gen_rtvec (1, XEXP (tmp, 0)));
+ }
}
break;
case MEM:
@@ -1355,6 +1355,10 @@ timode_scalar_chain::convert_insn (rtx_insn *insn)
tmp = find_reg_equal_equiv_note (insn);
if (tmp && GET_MODE (XEXP (tmp, 0)) == TImode)
PUT_MODE (XEXP (tmp, 0), V1TImode);
+ else if (tmp && CONST_SCALAR_INT_P (XEXP (tmp, 0)))
+ XEXP (tmp, 0) = gen_rtx_CONST_VECTOR (V1TImode,
+ gen_rtvec (1,
+ XEXP (tmp, 0)));
}
break;
case MEM:
new file mode 100644
@@ -0,0 +1,17 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -fno-dce -fno-forward-propagate -fno-rerun-cse-after-loop -Wno-psabi" } */
+
+typedef int V __attribute__((vector_size (64)));
+typedef __int128 W __attribute__((vector_size (64)));
+
+W w;
+V bar (void);
+
+void
+foo (V v, W)
+{
+ foo ((V){4, ~0}, (W) v);
+ foo (v, w);
+ bar ();
+}
+